Simplify the following expression: $z = \dfrac{2}{8a} \times \dfrac{8a}{10}$
When multiplying fractions, we multiply the numerators and the denominators. $z = \dfrac{ 2 \times 8a } { 8a \times 10}$ $z = \dfrac{16a}{80a}$ Simplify: $z = \dfrac{1}{5}$